1. Field of the Invention
The present invention relates to a midget gas turbine to be used as a supply source of electric power necessary for long time continuous use of various portable electric and electronic devices such as portable personal computers, portable communication terminals, video cameras and portable television sets in indoor or outdoor places where there is no electric utilities, and to be used as a heat source for preheating a fuel cell, serving also as an auxiliary electric power source for reducing a startup time of the fuel cell from its start to a full power operation, which was a demerit of a conventional fuel cell.
2. Discussion of Background
As an electric power source used for portable electric devices such as portable personal computers, portable communication terminals, portable printers, portable radio-cassette recorders, video cameras, portable television sets, etc., a rechargeable battery or a dry cell has been used. Technical developments have been made to these electric power sources to decrease the weight and to increase the electric energy to be stored.
On the other hand, technical developments to decrease electric power consumption of portable electric devices have also been seen. Due to a synergistic effect obtained by improving the performance of the power consuming devices and the performance of power sources, the continuous operational time is significantly increasing. However, in spite of these continuous technical developments, the principle of these electric power sources is still such that a chemical energy is stored and transformed into an electric energy for use, and as a result, there is a limit in available electric generation per weight. Therefore, there has been a demerit that extra batteries or many dry cells have to be carried for auxiliary use when a portable electric device is used for long time at an indoor or outdoor place where there is no electric utilities.
For example, in a case of live broadcasting of a sport program or a live show by using a portable PC, a digital camera and a communication terminal, the available time for continuous use for each of the devices is usually one or two hours because of its built-in batteries. For a live broadcasting of several hours or more than ten hours, a heavy storage battery or an electric generator was necessary as an additional equipment in order to supply a necessary electric power for long time.
Fuel cells have been expected as power sources for next generation vehicles or for medium or small-sized co-generation plants. Many technical developments have continuously been conducted to fuel cells. However, there is a major technical problem to be solved in that it takes a long startup time from its start to a full power operation. The current technique to a fuel cell has not been developed to such an extent that it has an excellent startup performance enabling a car to start moving immediately after turning a starter key like an automobile having a gasoline engine or a diesel engine in the conventional technique.